CVE-2020-35571 MantisBT XSS in manage_custom_field_update.php

What is CVE-2020-35571?

CVE-2020-35571 is a medium-severity cross-site scripting vulnerability in Mantisbt Mantisbt, published on 22 Feb 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

An issue was discovered in MantisBT through 2.24.3. In the helper_ensure_confirmed call in manage_custom_field_update.php, the custom field name is not sanitized. This may be problematic depending on CSP settings.

Weakness: CWE-79

Which versions are affected by CVE-2020-35571?

2 open source packages ship an affected version, including mantisbt/mantisbt. It affects 1 product.

Products include Mantisbt Mantisbt.

How do I fix CVE-2020-35571?

Upgrade mantisbt/mantisbt to 2.25.0 or later.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2020-35571 being exploited?

There is no known exploitation of CVE-2020-35571 in the wild and no public exploit code.

Other vulnerabilities in Mantisbt Mantisbt

• CVE-2019-15074 MantisBT allows cross-site scripting (XSS) via crafted filename Critical 9.6
• CVE-2026-30849 MantisBT SOAP API has an authentication bypass vulnerability on MySQL Critical 9.3
• CVE-2025-47776 MantisBT: Authentication bypass for some passwords due to PHP type juggling High 8.8
• CVE-2017-7615 MantisBT allows arbitrary password reset High 8.8
• CVE-2026-33517 MantisBT Vulnerable to Stored HTML Injection in Tag Delete Confirmation High 8.6

All Mantisbt Mantisbt vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-cvrm-cr3m-qj92.